Planetary transmissions with three interconnected gear sets

ABSTRACT

The family of transmissions has a plurality of members that can be utilized in powertrains to provide at least seven forward speed ratios and one reverse speed ratio. The transmission family members include three planetary gear sets having six torque-transmitting mechanisms and three fixed interconnections. The powertrain includes an engine and torque converter that is not continuously connected to one of the planetary gears members and an output member that is continuously connected with at one of the planetary gear members. The six torque-transmitting mechanisms provide interconnections between various gear members, the input shaft, the output shaft, and with the transmission housing, and are operated in combinations of three to establish at least seven forward speed ratios and one reverse speed ratio.

TECHNICAL FIELD

The present invention relates to a family of power transmissions havingthree planetary gear sets that are controlled by six torque-transmittingdevices to provide at least seven forward speed ratios and one reversespeed ratio.

BACKGROUND OF THE INVENTION

Passenger vehicles include a powertrain that is comprised of an engine,multi-speed transmission, and a differential or final drive. Themulti-speed transmission increases the overall operating range of thevehicle by permitting the engine to operate through its torque range anumber of times. The number of forward speed ratios that are availablein the transmission determines the number of times the engine torquerange is repeated. Early automatic transmissions had two speed ranges.This severely limited the overall speed range of the vehicle andtherefore required a relatively large engine that could produce a widespeed and torque range. This resulted in the engine operating at aspecific fuel consumption point during cruising, other than the mostefficient point. Therefore, manually-shifted (countershafttransmissions) were the most popular.

With the advent of three- and four-speed automatic transmissions, theautomatic shifting (planetary gear) transmission increased in popularitywith the motoring public. These transmissions improved the operatingperformance and fuel economy of the vehicle. The increased number ofspeed ratios reduces the step size between ratios and therefore improvesthe shift quality of the transmission by making the ratio interchangessubstantially imperceptible to the operator under normal vehicleacceleration.

It has been suggested that the number of forward speed ratios beincreased to six or more. Six-speed transmissions are disclosed in U.S.Pat. No. 4,070,927 issued to Polak on Jan. 31, 1978; U.S. Pat. No.6,071,208 issued to Koivunen on Jun. 6, 2000; U.S. Pat. No. 5,106,352issued to Lepelletier on Apr. 21, 1992; and U.S. Pat. No. 5,599,251issued to Beim and McCarrick on Feb. 4, 1997.

Six-speed transmissions offer several advantages over four andfive-speed transmissions, including improved vehicle acceleration andimproved fuel economy. While many trucks employ power transmissionshaving six or more forward speed ratios, passenger cars are stillmanufactured with three- and four-speed automatic transmissions andrelatively few five or six-speed devices due to the size and complexityof these transmissions. The Polak transmission provides six forwardspeed ratios with three planetary gear sets, two clutches, and threebrakes. The Koivunen and Beim patents utilize six torque-transmittingdevices including four brakes and two clutches to establish six forwardspeed ratios and a reverse ratio. The Lepelletier patent employs threeplanetary gear sets, three clutches and two brakes to provide sixforward speeds. One of the planetary gear sets is positioned andoperated to establish two fixed speed input members for the remainingtwo planetary gear sets.

Seven-speed transmissions are disclosed in U.S. Pat. No. 4,709,594 toMaeda; U.S. Pat. No. 6,053,839 to Baldwin et. al.; and U.S. Pat. No.6,083,135 to Baldwin et. al. Seven- and eight-speed transmissionsprovide further improvements in acceleration and fuel economy oversix-speed transmissions. However, like the six-speed transmissionsdiscussed above, the development of seven- and eight-speed transmissionshas been precluded because of complexity, size and cost.

SUMMARY OF THE INVENTION

It is an object of the present invention to provide an improved familyof transmissions having three planetary gear sets controlled to provideat least seven forward speed ratios and one reverse speed ratio.

In one aspect of the present invention, the family of transmissions hasthree planetary gear sets, each of which includes a first, second andthird member, which members may comprise a sun gear, a ring gear, or aplanet carrier assembly member.

In referring to the first, second and third gear sets in thisdescription and in the claims, these sets may be counted “first” to“third” in any order in the drawings (i.e., left to right, right toleft, etc.).

In another aspect of the present invention, each of the planetary gearsets may be of the single pinion-type or of the double pinion-type.

In yet another aspect of the present invention, the first member of thefirst planetary gear set is continuously interconnected with a firstmember of the second planetary gear set through a first interconnectingmember.

In yet another aspect of the present invention, the second member of thefirst planetary gear set is continuously interconnected with a firstmember of the third planetary gear set through a second interconnectingmember.

In yet another aspect of the present invention, the second member of thesecond planetary gear set is continuously interconnected with the secondmember of the third planetary gear set through a third interconnectingmember.

In yet a further aspect of the invention, each family memberincorporates an output shaft which is continuously connected with atleast one member of the planetary gear sets and an input shaft which isnot continuously connected with any member of the planetary gear sets.

In a further aspect of the invention, a first torque-transmittingmechanism, such as a clutch, selectively interconnects the input shaftwith a member of the first, second or third planetary gear set.

In still a further aspect of the invention, a second torque-transmittingmechanism, such as a clutch, selectively interconnects the input shaftwith a member of the first, second or third planetary gear set, or withthe first, second or third interconnecting member.

In another aspect of the invention, a third torque-transmittingmechanism, such as a clutch, selectively interconnects a member of thefirst, second or third planetary gear set with the input shaft, oranother member of the first, second or third planetary gear set.

In a still further aspect of the invention, a fourth torque-transmittingmechanism, such as a brake, selectively interconnects a member of thefirst, second or third planetary gear set or the first, second or thirdinterconnecting member with a stationary member.

In a further aspect of the invention, a fifth torque-transmittingmechanism, such as a brake, selectively interconnects a member of thefirst, second or third planetary gear set with the stationary member(transmission case).

In still another aspect of the invention, a sixth torque-transmittingmechanism, such as a clutch, selectively interconnects a member of thefirst, second or third planetary gear set with another member of thefirst, second or third planetary gear set. Alternatively, the fourthtorque transmitting mechanism, such as a brake, selectively connects amember of the first, second or third planetary gear set with astationary member (transmission case).

In still another aspect of the invention, the six torque-transmittingmechanisms are selectively engageable in combinations of three to yieldat least seven forward speed ratios and one reverse speed ratio.

The above object and other objects, features, and advantages of thepresent invention are readily apparent from the following detaileddescription of the best modes for carrying out the invention when takenin connection with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1a is a-schematic representation of a powertrain including aplanetary transmission incorporating a family member of the presentinvention;

FIG. 1b is a truth table and chart depicting some of the operatingcharacteristics of the powertrain shown in FIG. 1a;

FIG. 2a is a schematic representation of a powertrain having a planetarytransmission incorporating another family member of the presentinvention;

FIG. 2b is a truth table and chart depicting some of the operatingcharacteristics of the powertrain shown in FIG. 2a;

FIG. 3a is a schematic representation of a powertrain having a planetarytransmission incorporating another family member of the presentinvention;

FIG. 3b is a truth table and chart depicting some of the operatingcharacteristics of the powertrain shown in FIG. 3a;

FIG. 4a is a schematic representation of a powertrain having a planetarytransmission incorporating another family member of the presentinvention;

FIG. 4b is a truth table and chart depicting some of the operatingcharacteristics of the powertrain shown in FIG. 4a;

FIG. 5a is a schematic representation of a powertrain having a planetarytransmission incorporating another family member of the presentinvention;

FIG. 5b is a truth table and chart depicting some of the operatingcharacteristics of the powertrain shown in FIG. 5a;

FIG. 6a is a schematic representation of a powertrain having a planetarytransmission incorporating another family member of the presentinvention;

FIG. 6b is a truth table and chart depicting some of the operatingcharacteristics of the powertrain shown in FIG. 6a;

FIG. 7a is a schematic representation of a powertrain having a planetarytransmission incorporating another family member of the presentinvention;

FIG. 7b is a truth table and chart depicting some of the operatingcharacteristics of the powertrain shown in FIG. 7a;

FIG. 8a is a schematic representation of a powertrain having a planetarytransmission incorporating another family member of the presentinvention;

FIG. 8b is a truth table and chart depicting some of the operatingcharacteristics of the powertrain shown in FIG. 8a;

FIG. 9a is a schematic representation of a powertrain having a planetarytransmission incorporating another family member of the presentinvention;

FIG. 9b is a truth table and chart depicting some of the operatingcharacteristics of the powertrain shown in FIG. 9a;

FIG. 10a is a schematic representation of a powertrain having aplanetary transmission incorporating another family member of thepresent invention;

FIG. 10b is a truth table and chart depicting some of the operatingcharacteristics of the powertrain shown in FIG. 10a;

FIG. 11a is a schematic representation of a powertrain having aplanetary transmission incorporating another family member of thepresent invention;

FIG. 11b is a truth table and chart depicting some of the operatingcharacteristics of the powertrain shown in FIG. 11a;

FIG. 12a is a schematic representation of a powertrain having aplanetary transmission incorporating another family member of thepresent invention;

FIG. 12b is a truth table and chart depicting some of the operatingcharacteristics of the powertrain shown in FIG. 12a;

FIG. 13a is a schematic representation of a powertrain having aplanetary transmission incorporating another family member of thepresent invention;

FIG. 13b is a truth table and chart depicting some of the operatingcharacteristics of the powertrain shown in FIG. 13a;

FIG. 14a is a schematic representation of a powertrain having aplanetary transmission incorporating another family member of thepresent invention; and

FIG. 14b is a truth table and chart depicting some of the operatingcharacteristics of the powertrain shown in FIG. 14a.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring to the drawings, wherein like characters represent the same orcorresponding parts throughout the several views, there is shown in FIG.1a a powertrain 10 having a conventional engine and torque converter 12,a planetary transmission 14, and a conventional final drive mechanism16.

The planetary transmission 14 includes an input shaft 17 continuouslyconnected with the engine and torque converter 12, a planetary geararrangement 18, and an output shaft 19 continuously connected with thefinal drive mechanism 16. The planetary gear arrangement 18 includesthree planetary gear sets 20, 30 and 40.

The planetary gear set 20 includes a sun gear member 22, a ring gearmember 24, and a planet carrier assembly 26. The planet carrier assembly26 includes a plurality of pinion gears 27 rotatably mounted on acarrier member 29 and disposed in meshing relationship with both the sungear member 22 and the ring gear member 24.

The planetary gear set 30 includes a sun gear member 32, a ring gearmember 34, and a planet carrier assembly member 36. The planet carrierassembly member 36 includes a plurality of pinion gears 37 rotatablymounted on a carrier member 39 and disposed in meshing relationship withboth the sun gear member 32 and the ring gear member 34.

The planetary gear set 40 includes a sun gear member 42, a ring gearmember 44, and a planet carrier assembly member 46. The planet carrierassembly member 46 includes a plurality of pinion gears 47 rotatablymounted on a carrier member 49 and disposed in meshing relationship withboth the sun gear member 42 and the ring gear member 44.

The planetary gear arrangement also includes six torque-transmittingmechanisms 50, 52, 54, 56, 58 and 59. The torque-transmitting mechanisms50, 52, 54 and 56 are rotating-type torque-transmitting mechanisms,commonly termed clutches. The torque-transmitting mechanisms 58 and 59are stationary-type torque-transmitting mechanisms, commonly termedbrakes or reaction clutches.

The input shaft 17 is not continuously connected with any planetary gearmember. The output shaft 19 is continuously connected with the ring gearmember 24. The planet carrier assembly member 26 is continuouslyconnected with the planet carrier assembly member 36 through theinterconnecting member 70. The sun gear member 22 is continuouslyconnected with the planet carrier assembly member 46 through theinterconnecting member 72. The sun gear member 32 is continuouslyconnected with the ring gear member 44 through the interconnectingmember 74.

The planet carrier assembly member 36 is selectively connectable withthe input shaft 17 through the clutch 50. The ring gear member 34 isselectively connectable with the input shaft 17 through the clutch 52.The sun gear-member 42 is selectively connectable with the input shaft17 through the clutch 54. The planet carrier assembly member 46 isselectively connectable with the sun gear member 42 through the clutch56. The planet carrier assembly member 26 is selectively connectablewith the transmission housing 60 through the brake 58. The sun gearmember 42 is selectively connectable with the transmission housing 60through the brake 59.

As shown in FIG. 1b, and in particular the truth table disclosedtherein, the torque-transmitting mechanisms are selectively engaged incombinations of three to provide seven forward speed ratios and areverse speed ratio. It should also be noted in the truth table that thetorque-transmitting mechanisms 54 and 58 remain engaged through aneutral condition, thereby simplifying the forward/reverse interchange.

The reverse speed ratio is established with the engagement of theclutches 54, 56 and the brake 58. The clutch 54 connects the sun gearmember 42 to the input shaft 17. The clutch 56 connects the planetcarrier assembly member 46 with the sun gear member 42. The brake 58connects the planet carrier assembly member 26 to the transmissionhousing 60. The sun gear member 22, the planet carrier assembly member46 and the sun gear member 42 rotate at the same speed as the inputshaft 17. The planet carrier assembly members 26 and 36 do not rotate.The ring gear member 24 rotates at the same speed as the output shaft19. The ring gear member 24, and therefore the output shaft 19, rotatesat a speed determined from the speed of the sun gear member 22 and thering gear/sun gear tooth ratio of the planetary gear set 20. The sungear member 32 rotates at the same speed as the ring gear member 44. Thenumerical value of the reverse speed ratio is determined utilizing thering gear/sun gear tooth ratio of the planetary gear set 20.

The first forward speed ratio is established with the engagement of theclutches 52, 54 and the brake 58. The clutch 52 connects the ring gearmember 34 to the input shaft 17. The clutch 54 connects the sun gearmember 42 to the input shaft 17. The brake 58 connects the planetcarrier assembly member 26 to the transmission housing 60. The sun gearmember 22 rotates at the same speed as the planet carrier assemblymember 46. The planet carrier assembly members 26 and 36 do not rotate.The ring gear member 24 rotates at the same speed as the output shaft19. The ring gear member 24, and therefore the output shaft 19, rotatesat a speed determined from the speed of the sun gear member 22 and thering gear/sun gear tooth ratio of the planetary gear set 20. The sungear member 32 rotates at the same speed as the ring gear member 44. Thering gear member 34, the sun gear member 42 and the input shaft 17rotate at the same speed. The ring gear member 34 rotates at a speeddetermined from the speed of the sun gear member 32 and the ringgear/sun gear tooth ratio of the planetary gear set 30. The planetcarrier assembly member 46 rotates at the speed determined from thespeed of the ring gear member 44, the speed of the sun gear member 42and the ring gear/sun gear tooth ratio of the planetary gear set 40. Thenumerical value of the first forward speed ratio is determined utilizingthe ring gear/sun gear tooth ratios of the planetary gear sets 20, 30and 40.

The second forward speed ratio is established with the engagement of theclutch 52 and the brakes 58, 59. The clutch 52 connects the ring gearmember 34 to the input shaft 17. The brake 58 connects the planetcarrier assembly member 26 to the transmission housing 60. The brake 59connects the sun gear member 42 to the transmission housing 60. The sungear member 22 rotates at the same speed as the planet carrier assemblymember 46. The planet carrier assembly members 26 and 36 do not rotate.The ring gear member 24 rotates at the same speed as the output shaft19. The ring gear member 24, and therefore the output shaft 19, rotatesat a speed determined from-the speed of the sun gear member 22 and thering gear/sun gear tooth ratio of the planetary gear set 20. The sungear member 32 rotates at the same speed as the ring gear member 44. Thering gear member 34 rotates at the same speed as the input shaft 17. Thering gear member 34 rotates at a speed determined from the speed of thesun gear member 32 and the ring gear/sun gear tooth ratio of theplanetary gear set 30. The sun gear member 42 does not rotate. Theplanet carrier assembly member 46 rotates at a speed determined from thespeed of the ring gear member 44 and the ring gear/sun gear tooth ratioof the planetary gear set 40. The numerical value of the second forwardspeed ratio is determined utilizing the ring gear/sun gear tooth ratiosof the planetary gear sets 20, 30 and 40.

The third forward speed ratio is established with the engagement of theclutches 52, 56 and the brake 58. The clutch 52 connects the ring gearmember 34 to the input shaft 17. The clutch 56 connects the planetcarrier assembly member 46 to the sun gear member 42. The brake 58connects the planet carrier assembly member 26 to the transmissionhousing 60. The sun gear member 22 rotates at the same speed as theplanet carrier assembly member 46 and the sun gear member 42. The planetcarrier assembly members 26 and 36 do not rotate. The ring gear member24 rotates at the same speed as the output shaft 19. The ring gearmember 24, and therefore the output shaft 19, rotates at a speeddetermined from the speed of the sun gear member 22 and the ringgear/sun gear tooth ratio of the planetary gear set 20. The sun gearmember 32 rotates at the same speed as the ring gear member 44. The ringgear member 34 rotates at the same speed as the input shaft 17. The ringgear member 34 rotates at a speed determined from the speed of the sungear member 32 and the ring gear/sun gear tooth ratio of the planetarygear set 30. The numerical value of the third forward speed ratio isdetermined utilizing the ring gear/sun gear tooth ratios of theplanetary gear sets 20 and 30.

The fourth forward speed ratio is established with the engagement of theclutches 52, 56 and the brake 59. The clutch 52 connects the ring gearmember 34 to the input shaft 17. The clutch 56 connects the planetcarrier assembly member 46 to the sun gear member 42. The brake 59connects the sun gear member 42 to the transmission housing 60. The sungear member 22, the planet carrier assembly member 46 and the sun gearmember 42 do not rotate. The planet carrier assembly member 26 rotatesat the same speed as the planet carrier assembly member 36. The ringgear member 24 rotates at the same speed as the output shaft 19. Thering gear member 24, and therefore the output shaft 19, rotates at aspeed determined from the speed of the planet carrier assembly member 26and the ring gear/sun gear tooth ratio of the planetary gear set 20. Thesun gear member 32 and planetary gear set 40 do not rotate. The ringgear member 34 rotates at the same speed as the input shaft 17. Theplanet carrier assembly member 36 rotates a speed determined from thespeed of the ring gear member 34 and the ring gear/sun gear tooth ratioof the planetary gear set 30. The numerical value of the fourth forwardspeed ratio is determined utilizing the ring gear/sun gear tooth ratiosof the planetary gear sets 20 and 30.

The fifth forward speed ratio is established with the engagement of theclutches 50, 52 and 56. In this configuration, the input shaft 17 isdirectly connected to the output shaft 19. The numerical value of thefifth forward speed ratio is 1.

The sixth forward speed ratio is established with the engagement of theclutches 50, 52 and the brake 59. The clutch 50 connects the planetcarrier assembly member 36 to the input shaft 17. The clutch 52 connectsthe ring gear member 34 to the input shaft 17. The brake 59 connects thesun gear member 42 to the transmission housing 60. The sun gear member22 rotates at the same speed as the planet carrier assembly member 46.The planet carrier assembly member 26, the planet carrier assemblymember 36 and the ring gear member 34 rotate at the same speed as theinput shaft 17. The ring gear member 24 rotates at the same speed as theoutput shaft 19. The ring gear member 24, and therefore the output shaft19, rotates at a speed determined from the speed of the planet carrierassembly member 26, the speed of the sun gear member 22 and the ringgear/sun gear tooth ratio of the planetary gear set 20. The sun gearmember 32 rotates at the same speed as the ring gear member 44. The sungear member 42 does not rotate. The planet carrier assembly member 46rotates at a speed determined from the speed of the ring gear member 44and the ring gear/sun gear tooth ratio of the planetary gear set 40. Thenumerical value of the sixth forward speed ratio is determined utilizingthe ring gear/sun gear tooth ratios of the planetary gear sets 20 and40.

The seventh forward speed ratio is established with the engagement ofthe clutches 50, 56 and the brake 59. The clutch 50 connects the planetcarrier assembly member 36 to the input shaft 17. The clutch 56 connectsthe planet carrier assembly member 46 to the sun gear member 42. Thebrake 59 connects the sun gear member 42 to the transmission housing 60.The sun gear members 22 and 32, and the planetary gear set 40 do notrotate. The planet carrier assembly members 26 and 36 rotate at the samespeed as the input shaft 17. The ring gear member 24 rotates at the samespeed as the output shaft 19. The ring gear member 24, and therefore theoutput shaft 19, rotates at a speed determined from the speed of theplanet carrier assembly member 26 and the ring gear/sun gear tooth ratioof the planetary gear set 20. The numerical value of the seventh forwardspeed ratio is determined utilizing the ring gear/sun gear tooth ratioof the planetary gear set 20.

As set forth above, the engagement schedule for the torque-transmittingmechanisms is shown in the truth table of FIG. 1b. This truth table alsoprovides an example of speed ratios that are available utilizing thering gear/sun gear tooth ratios given by way of example in FIG. 1b. TheR1/S1 value is the tooth ratio of the planetary gear set 20; the R2/S2value is the tooth ratio of the planetary gear set 30; and the R3/S3value is the tooth ratio of the planetary gear set 40. Also, the chartof FIG. 1b describes the ratio steps that are attained utilizing thesample of tooth ratios given. For example, the step ratio between thefirst and second forward speed ratios is 1.79, while the step ratiobetween the reverse and first forward ratio is −.51.

FIG. 2a shows a powertrain 110 having a conventional engine and torqueconverter 12, a planetary transmission 114, and a conventional finaldrive mechanism 16.

The planetary transmission 114 includes an input shaft 17 continuouslyconnected with the engine and torque converter 12, a planetary geararrangement 118, and an output shaft 19 continuously connected with thefinal drive mechanism 16. The planetary gear arrangement 118 includesthree planetary gear sets 120, 130 and 140.

The planetary gear set 120 includes a sun gear member 122, a ring gearmember 124, and a planet carrier assembly 126. The planet carrierassembly 126 includes a plurality of pinion gears 127 rotatably mountedon a carrier member 129 and disposed in meshing relationship with boththe sun gear member 122 and the ring gear member 124.

The planetary gear set 130 includes a sun gear member 132, a ring gearmember 134, and a planet carrier assembly member 136. The planet carrierassembly member 136 includes a plurality of pinion gears 137 rotatablymounted on a carrier member 139 and disposed in meshing relationshipwith both the sun gear member 132 and the ring gear member 134.

The planetary gear set 140 includes a sun gear member 142, a ring gearmember 144, and a planet carrier-assembly member 146. The planet carrierassembly member 146 includes a plurality of pinion gears 147 rotatablymounted on a carrier member 149 and disposed in meshing relationshipwith both the sun gear member 142 and the ring gear member 144.

The planetary gear arrangement 118 also includes six torque-transmittingmechanisms 150, 152, 154, 156, 158 and 159. The torque-transmittingmechanisms 150, 152, 154 and 156 are rotating-type torque-transmittingmechanisms, commonly termed “clutches.” The torque-transmittingmechanisms 158 and 159 are stationary-type torque-transmittingmechanisms, commonly termed brakes or reaction clutches.

The input shaft 17 is not continuously connected with any planetary gearmember. The output shaft 19 is continuously connected with the ring gearmember 124. The planet carrier assembly member 126 is continuouslyconnected with the planet carrier assembly member 136 through theinterconnecting member 170. The sun gear member 122 is continuouslyconnected with the planet carrier assembly member 146 through theinterconnecting member 172. The sun gear member 132 is continuouslyconnected with the ring gear member 144 through the interconnectingmember 174.

The planet carrier assembly member 136 is selectively connectable withthe input shaft 17 through the clutch 150. The ring gear member 134 isselectively connectable with the input shaft 17 through the clutch 152.The sun gear member 142 is selectively connectable with the input shaft17 through the clutch 154. The ring gear member 144 is selectivelyconnectable with the planet carrier assembly member 146 through theclutch 156. The planet carrier assembly member 126 is selectivelyconnectable with the transmission housing 160 through the brake 158. Thesun gear member 142 is selectively connectable with the transmissionhousing 160 through the brake 159.

The truth table of FIG. 2b describes the engagement sequence utilized toprovide seven forward speed ratios and a reverse speed ratio in theplanetary gear arrangement 118 shown in FIG. 2a.

The reverse speed ratio is established with the engagement of theclutches 154, 156 and the brake 158. The clutch 154 connects the sungear member 142 to the input shaft 17. The clutch 156 connects the ringgear member 144 to the planet carrier assembly member 146. The brake 158connects the planet carrier assembly member 126 to the transmissionhousing 160. The sun gear member 122, the sun gear member 132, and theplanetary gear set 140 rotate at the same speed as the input shaft 17.The planet carrier assembly members 126 and 136 do not rotate. The ringgear member 124 rotates at the same speed as the output shaft 19. Thering gear member 124, and therefore the output shaft 19, rotates at aspeed determined from the speed of the sun gear member 122 and the ringgear/sun gear tooth ratio of the planetary gear set 120. The numericalvalue of the reverse speed ratio is determined utilizing the ringgear/sun gear tooth ratio of the planetary gear set 120.

The first forward speed ratio is established with the engagement of theclutches 152, 154 and the brake 158. The clutch 152 connects the ringgear member 134 to the input shaft 17. The clutch 154 connects the sungear member 142 to the input shaft 17. The brake 158 connects the planetcarrier assembly member 126 to the transmission housing 160. The sungear member 122 rotates at the same speed as the planet carrier assemblymember 146. The planet carrier assembly member 126 and the planetcarrier assembly member 136 do not rotate. The ring gear member 124rotates at the same speed as the output shaft 19. The ring gear member124, and therefore the output shaft 19, rotates at a speed determinedfrom the speed of the sun gear member 122 and the ring gear/sun geartooth ratio of the planetary gear set 120. The sun gear-member 132rotates at the same speed as the ring gear member 144. The ring gearmember 134 and the sun gear member 142 rotate at the same speed as theinput shaft 17. The sun gear member 132 rotates at a speed determinedfrom the speed of the ring gear member 134 and the ring gear/sun geartooth ratio of the planetary gear set 130. The planet carrier assemblymember 146 rotates at a speed determined from the speed of the ring gearmember 144, the speed of the sun gear member 142 and the ring gear/sungear tooth ratio of the planetary gear set 140. The numerical value ofthe first forward speed ratio is determined utilizing the ring gear/sungear tooth ratios of the planetary gear sets 120, 130 and 140.

The second forward speed ratio is established with the engagement of theclutch 152 and the brakes 158, 159. The clutch 152 connects the ringgear member 134 to the input shaft 17. The brake 158 connects the planetcarrier assembly member 126 to the transmission housing 160. The brake159 connects the sun gear member 142 to the transmission housing 160.The sun gear member 122 rotates at the same speed as the planet carrierassembly member 146. The planet carrier assembly members 126 and 136 donot rotate. The ring gear member 124 rotates at the same speed as theoutput shaft 19. The ring gear member 124, and therefore the outputshaft 19, rotates at a speed determined from the speed of the sun gearmember 122 and the ring gear/sun gear tooth ratio of the planetary gearset 120. The sun gear member 132 rotates at the same speed as the ringgear member 144. The ring gear member 134 rotates at the same speed asthe input shaft 17. The sun gear member 132 rotates at a speeddetermined from the speed of the ring gear member 134 and the ringgear/sun gear tooth ratio of the planetary gear set 130. The sun gearmember 142 does not rotate. The planet carrier assembly member 146rotates at a speed determined from the speed of the ring gear member 144and the ring gear/sun gear tooth ratio of the planetary gear set 140.The numerical value of the second forward speed ratio is determinedutilizing the ring gear/sun gear tooth ratios of the planetary gear sets120, 130 and 140.

The third forward speed ratio is established with the engagement of theclutches 152, 156 and the brake 158. The clutch 152 connects the ringgear member 134 to the input shaft 17. The clutch 156 connects the ringgear member 144 to the planet carrier assembly member 146. The brake 158connects the planet carrier assembly member 126 to the transmissionhousing 160. The sun gear member 122, the sun gear member 132, the ringgear member 144 and the planet carrier assembly member 146 rotate at thesame speed. The planet carrier assembly members 126 and 136 do notrotate. The ring gear member 124 rotates at the same speed as the outputshaft 19. The ring gear member 124, and therefore the output shaft 19,rotates at a speed determined from the speed of the sun gear member 122and the ring gear/sun gear tooth ratio of the planetary gear set 120.The ring gear member 134 rotates at the same speed as the input shaft17. The sun gear member 132 rotates at a speed determined from the speedof the ring gear member 134 and the ring gear/sun gear tooth ratio ofthe planetary gear set 130. The numerical value of the third forwardspeed ratio is determined utilizing the ring gear/sun gear tooth ratiosof the planetary gear sets 120 and 130.

The fourth forward speed ratio is established with the engagement of theclutches 152, 156 and the brake 159. The clutch 152 connects the ringgear member 134 to the input shaft 17. The clutch 156 connects the ringgear member 144 to the planet carrier assembly member 146. The brake 159connects the sun gear member 142 to the transmission housing 160. Thesun gear member 122, the sun gear member 132, and the planetary gear set140 do not rotate. The planet carrier assembly member 126 rotates at thesame speed as the planet carrier assembly member 136. The ring gearmember 124 rotates at the same speed as the output shaft 19. The ringgear member 124, and therefore the output shaft 19, rotates at a speeddetermined from the speed of the planet carrier assembly member 126 andthe ring gear/sun gear tooth ratio of the planetary gear set 120. Thering gear member 134 rotates at the same speed as the input shaft 17.The planet carrier assembly member 136 rotates at a speed determinedfrom the speed of the ring gear member 134 and the ring gear/sun geartooth ratio of the planetary gear set 130. The numerical value of thefourth forward speed ratio is determined utilizing the ring gear/sungear tooth ratios of the planetary gear sets 120 and 130.

The fifth forward speed ratio is established with the engagement of theclutches 150, 152 and 156. In this configuration, the input shaft 17 isdirectly connected to the output shaft 19. The numerical value of thefifth forward speed ratio is 1.

The sixth forward speed ratio is established with the engagement of theclutches 150, 152 and the brake 159. The clutch 150 connects the planetcarrier assembly member 136 to the input shaft 17. The clutch 152connects the ring gear member 134 to the input shaft 17. The brake 159connects the sun gear member 142 to the transmission housing 160. Thesun gear member 122 rotates at the same speed as the planet carrierassembly member 146. The planet carrier assembly member 126, the planetcarrier assembly member 136 and the ring gear member 134 rotate at thesame speed as the input shaft 17. The ring gear member 124 rotates atthe same speed as the output shaft 19. The ring gear member 124, andtherefore the output shaft 19, rotates at a speed determined from thespeed of the planet carrier assembly member 126, the speed of the sungear member 122 and the ring gear/sun gear tooth ratio of the planetarygear set 120. The sun gear member 132 rotates at the same speed as thering gear member 144. The sun gear member 142 does not rotate. Theplanet carrier assembly member 146 rotates at a speed determined fromthe speed of the ring gear member 144 and the ring gear/sun gear toothratio of the planetary gear set 140. The numerical value of the sixthforward speed ratio is determined utilizing the ring gear/sun gear toothratios of the planetary gear sets 120 and 140.

The seventh forward speed ratio is established with the engagement ofthe clutches 150, 156 and the brake 159. The clutch 150 connects theplanet carrier assembly member 136 to the input shaft 17. The clutch 156connects the ring gear member 144 to the planet carrier assembly member146. The brake 159 connects the sun gear member 142 to the transmissionhousing 160. The sun gear member 122, the sun gear member 132, and theplanetary gear set 140 do not rotate. The planet carrier assemblymembers 126 and 136 rotate at the same speed as the input shaft 17. Thering gear member 124 rotates at the same speed as the output shaft 19.The ring gear member 124, and therefore the output shaft 19, rotates ata speed determined from the speed of the planet carrier assembly member126 and the ring gear/sun gear tooth ratio of the planetary gear set120. The numerical value of the seventh forward speed ratio isdetermined utilizing the ring gear/sun gear tooth ratio of the planetarygear set 120.

As set forth above, the truth table of FIG. 2b describes the engagementsequence of the torque-transmitting mechanisms utilized to provide areverse drive ratio and seven forward speed ratios. It can be readilydetermined from the truth table that all of the single step forwardinterchanges are of the single transition type, as are the double stepforward interchanges. The truth table also provides an example of theratios that can be attained with the family members shown in FIG. 2autilizing the sample tooth ratios given in FIG. 2b. The R1/S1 value isthe tooth ratio of the planetary gear set 120; the R2/S2 value is thetooth ratio of the planetary gear set 130; and the R3/S3 value-is thetooth ratio of the-planetary gear set 140. Also shown in FIG. 2b are theratio steps between single step ratios in the forward direction as wellas the reverse to first ratio step ratio. For example, the first tosecond step ratio is 1.79.

Turning to FIG. 3a, a powertrain 210 includes the engine and torqueconverter 12, a planetary transmission 214, and a final drive mechanism16. The planetary transmission 214 includes an input shaft 17continuously connected with the engine and torque converter 12, aplanetary gear arrangement 218, and an output shaft 19 continuouslyconnected with the final drive mechanism 16. The planetary geararrangement 218 includes three planetary gear sets 220, 230 and 240.

The planetary gear set 220 includes a sun gear member 222, a ring gearmember 224, and a planet carrier assembly 226. The planet carrierassembly 226 includes a plurality of pinion gears 227 rotatably mountedon a carrier member 229 and disposed in meshing relationship with boththe sun gear member 222 and the ring gear member 224.

The planetary gear set 230 includes a sun gear member 232, a ring gearmember 234, and a planet carrier assembly member 236. The planet carrierassembly member 236 includes a plurality of pinion gears 237 rotatablymounted on a carrier member 239 and disposed in meshing relationshipwith both the sun gear member 232 and the ring gear member 234.

The planetary gear set 240 includes a sun gear member 242, a ring gearmember 244, and a planet carrier assembly member 246. The planet carrierassembly member 246 includes a plurality of pinion gears 247 rotatablymounted on a carrier member 249 and disposed in meshing relationshipwith both the sun gear member 242 and the ring gear member 244.

The planetary gear arrangement 218 also includes six torquetransmitting-mechanisms 250, 252, 254, 256, 258 and 259. Thetorque-transmitting mechanisms 250, 252, 254 and 256 are rotating typetorque-transmitting mechanisms, commonly termed clutches. Thetorque-transmitting mechanisms 258 and 259 are stationary typetorque-transmitting mechanisms, commonly termed brakes or reactionclutches.

The input shaft 17 is not continuously connected with any planetary gearmember. The output shaft 19 is continuously connected with the planetcarrier assembly member 246. The ring gear member 224 is continuouslyconnected with the planet carrier assembly member 236 through theinterconnecting member 270. The ring gear member 244 is continuouslyconnected with the planet carrier assembly member 226 through theinterconnecting member 272. The sun gear member 232 is continuouslyconnected with the sun gear member 242 through the interconnectingmember 274.

The planet carrier assembly member 236 is selectively connectable withthe input shaft 17 through the clutch 250. The sun gear member 232 isselectively connectable with the input shaft 17 through the clutch 252.The planet carrier assembly member 226 is selectively connectable withthe ring gear member 234 through the clutch 254. The sun gear member 222is selectively connectable with the ring gear member 234 through theclutch 256. The planet carrier assembly member 236 is selectivelyconnectable with the transmission housing 260 through the brake 258. Thesun gear member 222 is selectively connectable with the transmissionhousing 260 through the brake 259.

As shown in the truth table in FIG. 3b, the torque-transmittingmechanisms are engaged in combinations of three to establish eightforward speed ratios and one reverse ratio.

The reverse speed ratio is established with the engagement of theclutches 252, 254 and the brake 258. The clutch 252 connects the sungear member 232 to the input shaft 17. The clutch 254 connects theplanet carrier assembly member 226 to the ring gear member 234. Thebrake 258 connects the planet carrier assembly member 236 to thetransmission housing 260. The planet carrier assembly member 226, thering gear member 234 and the ring gear member 244 rotate at the samespeed. The ring gear member 224 and the planet carrier assembly member236 do not rotate. The sun gear members 232 and 242 rotate at the samespeed as the input shaft 17. The ring gear member 234 rotates at a speeddetermined from the speed of the sun gear member 232 and the ringgear/sun gear tooth ratio of the planetary gear set 230. The planetcarrier assembly member 246 rotates at the same speed as the outputshaft 19. The planet carrier assembly member 246, and therefore theoutput shaft 19, rotates at a speed determined from the speed of thering gear member 244, the speed of the sun gear member 242 and the ringgear/sun gear tooth ratio of the planetary gear set 240. The numericalvalue of the reverse speed ratio is determined utilizing the ringgear/sun gear tooth ratios of the planetary gear sets 230 and 240.

The first forward speed ratio is established with the engagement of theclutches 252, 256 and the brake 258. The clutch 252 connects the planetcarrier assembly member 232 to the input shaft 17. The clutch 256connects the sun gear member 222 to the ring gear member 234. The brake258 connects the planet carrier assembly member 236 to the transmissionhousing 260. The sun gear member 222 rotates at the same speed as thering gear member 234. The planet carrier assembly member 226 rotates atthe same speed as the ring gear member 244. The ring gear member 224 andthe planet carrier assembly member 236 do not rotate. The planet carrierassembly member 226 rotates at a speed determined from the speed of thesun gear member 222 and the ring gear/sun gear tooth ratio of theplanetary gear set 220. The sun gear members 232 and 242 rotate at thesame speed as the input shaft 17. The ring gear member 234 rotates at aspeed determined from the speed of the sun gear member 232 and the ringgear/sun gear tooth ratio of the planetary gear set 230. The planetcarrier assembly member 246 rotates at the same speed as the outputshaft 19. The planet carrier assembly member 246, and therefore theoutput shaft 19, rotates at a speed determined from the speed of the sungear member 242, the speed of the ring gear member 244 and the ringgear/sun gear tooth ratio of the planetary gear set 240. The numericalvalue of the first forward speed ratio is determined utilizing the ringgear/sun gear tooth ratios of the planetary gear sets 220, 230 and 240.

The second forward speed ratio is established with the engagement of theclutch 252 and the brakes 258, 259. The clutch 252 connects the sun gearmember 232 to the input shaft 17. The brake 258 connects the planetcarrier assembly member 236 to the transmission housing 260. The brake259 connects the sun gear member 222 to the transmission housing 260.The planetary gear set 220, the planet carrier assembly member 236 andthe ring gear member 244 do not rotate. The sun gear members 232 and 242rotate at the same speed as the input shaft 17. The planet carrierassembly member 246 rotates at the same speed as the output shaft 19.The planet carrier assembly member 246, and therefore the output shaft19, rotates at a speed determined from the speed of the sun gear member242 and the ring gear/sun gear tooth ratio of the planetary gear set240. The numerical value of the second forward speed ratio is determinedutilizing the ring gear/sun gear tooth ratio of the planetary gear set240.

The third forward speed ratio is established with the engagement of theclutches 252, 256 and the brake 259. The clutch 252 connects the sungear member 232 to the input shaft 17. The clutch 256 connects the sungear member 222 to the ring gear member 234. The brake 259 connects thesun gear member 222 to the transmission housing 260. The sun gear member222 and the ring gear member 234 do not rotate. The planet carrierassembly member 226 rotates at the same speed as the ring gear member244. The ring gear member 224 rotates at the same speed as the planetcarrier assembly member 236. The planet carrier assembly member 226rotates at a speed determined from the speed of the ring gear member 224and the ring gear/sun gear tooth ratio of the planetary gear set 220.The sun gear members 232 and 242 rotate at the same speed as the inputshaft 17. The planet carrier assembly member 236 rotates at a speeddetermined from the speed of the sun gear member 232 and the ringgear/sun gear tooth ratio of the planetary gear set 230. The planetcarrier assembly member 246 rotates at the same speed as the outputshaft 19. The planet carrier assembly member 246, and therefore theoutput shaft 19, rotates at a speed determined from the speed of thering gear member 244, the speed of the sun gear member 242 and the ringgear/sun gear tooth ratio of the planetary gear set 240. The numericalvalue of the third forward speed ratio is determined utilizing the ringgear/sun gear tooth ratios of the planetary gear sets 220, 230 and 240.

The fourth forward speed ratio is established with the engagement of theclutches 252, 254 and the brake 259. The clutch 252 connects the sungear member 232 to the input shaft 17. The clutch 254 connects theplanet carrier assembly member 226 to the ring gear member 234. Thebrake 259 connects the sun gear member 222 to the transmission housing260. The sun gear member 222 does not rotate. The planet carrierassembly member 226, the ring gear member 234 and the ring gear member244 rotate at the same speed. The ring gear member 224 rotates at thesame speed as the planet carrier assembly member 236. The planet carrierassembly member 226 rotates at a speed determined from the speed of thering gear member 224 and the ring gear/sun gear tooth ratio of theplanetary gear set 220. The sun gear members 232 and 242 rotate at thesame speed as the input shaft 17. The planet carrier assembly member 236rotates at a speed determined from the speed of the ring gear member234, the speed of the sun gear member 232 and the ring gear/sun geartooth ratio of the planetary gear set 230. The planet carrier assemblymember 246 rotates at the same speed as the output shaft 19. The planetcarrier assembly member 246, and therefore the output shaft 19, rotatesat a speed determined from the speed of the ring gear member 244, thespeed of the sun gear member 242 and the ring gear/sun gear tooth ratioof the planetary gear set 240. The numerical value of the fourth forwardspeed ratio is determined utilizing the ring gear/sun gear tooth ratiosof the planetary gear sets 220, 230 and 240.

The fifth forward speed ratio is established with the engagement of theclutches 250, 252 and the brake 259. The clutch 250 connects the planetcarrier assembly member 236 to the input shaft 17. The clutch 252connects the sun gear member 232 to the input shaft 17. The brake 259connects the sun gear member 222 to the transmission housing 260. Thesun gear member 222 does not rotate. The planet carrier assembly member226 rotates at the same speed as the ring gear member 244. The ring gearmember 224, the planet carrier assembly member 236, the sun gear member232 and the sun gear member 242 rotate at the same speed as the inputshaft 17. The planet carrier assembly member 226 rotates at the speeddetermined from the speed of the ring gear member 224 and the ringgear/sun gear tooth ratio of the planetary gear set 220. The planetcarrier assembly member 246 rotates at the same speed as the outputshaft 19. The planet carrier assembly member 246, and therefore theoutput shaft 19, rotates at a speed determined from the speed of thering gear member 244, the speed of the sun gear member 242 and the ringgear/sun gear tooth ratio of the planetary gear set 240. The numericalvalue of the fifth forward speed ratio is determined utilizing the ringgear/sun gear tooth ratios of the planetary gear sets 220 and 240.

The sixth forward speed ratio is established with the engagement of theclutches 250, 254 and the brake 259. The clutch 250 connects the planetcarrier assembly member 236 to the input shaft 17. The clutch 254connects the planet carrier assembly member 226 to the ring gear member234. The brake 259 connects the sun gear member 222 to the transmissionhousing 260. The sun gear member 222 does not rotate. The planet carrierassembly member 226, the ring gear member 234 and the ring gear member244 rotate at the same speed. The ring gear member 224 and the planetcarrier assembly member 236 rotate at the same speed as the input shaft17. The planet carrier assembly member 226 rotates at a speed determinedfrom the speed of the ring gear member 224 and the ring gear/sun geartooth ratio of the planetary gear set 220. The sun gear member 232rotates at the same speed as the sun gear member 242. The ring gearmember 234 rotates at a speed determined from the speed of the planetcarrier assembly member 236, the speed of the sun gear member 232 andthe ring gear/sun gear tooth ratio of the planetary gear set 230. Theplanet carrier assembly member 246 rotates at the same speed as theoutput shaft 19. The planet carrier assembly member 246, and thereforethe output shaft 19, rotates at a speed determined from the speed of thering gear member 244, the speed of the sun gear member 242 and the ringgear/sun gear tooth ratio of the planetary gear set 240. The numericalvalue of the sixth forward speed ratio is determined utilizing the ringgear/sun gear tooth ratios of the planetary gear sets 220, 230 and 240.

The seventh forward speed ratio is established with the engagement ofthe clutch 250, 254 and 256. In this configuration, the input shaft 17is directly connected to the output shaft 19. The numerical value of theseventh forward speed ratio is 1.

The eighth forward speed ratio is established with the engagement of theclutches 250, 256 and the brake 259. The clutch 250 connects the planetcarrier assembly member 236 to the input shaft 17. The clutch 256connects the sun gear member 222 to the ring gear member 234. The brake259 connects the sun gear member 222 to the transmission housing 260.The sun gear member 222 and the ring gear member 234 do not rotate. Theplanet carrier assembly member 226 rotates at the same speed as the ringgear member 244. The ring gear member 224 and the planet carrierassembly member 236 rotate at the same speed as the input shaft 17. Theplanet carrier assembly member 226 rotates at a speed determined fromthe speed of the ring gear member 224 and the ring gear/sun gear toothratio of the planetary gear set 220. The sun gear member 232 rotates atthe same speed as the sun gear member 242. The planet carrier assemblymember 236 rotates at a speed determined from the speed of the sun gearmember 232 and the ring gear/sun gear tooth ratio of the planetary gearset 230. The planet carrier assembly member 246 rotates at the samespeed as the output shaft 19. The planet carrier assembly member 246,and therefore the output shaft 19, rotates at a speed determined fromthe speed of the ring gear member 244, the speed of the sun gear member242 and the ring gear/sun gear tooth ratio of the planetary gear set240. The numerical value of the eighth forward speed ratio is determinedutilizing the ring gear/sun gear tooth ratios of the planetary gear sets220, 230 and 240.

As previously set forth, the truth table of FIG. 3b describes thecombinations of engagements utilized for the eight forward speed ratiosand reverse ratio. The truth table also provides an example of speedratios that are available with the family member described above. Theseexamples of speed ratios are determined utilizing the tooth ratios givenin FIG. 3b. The R1/S1 value is the tooth ratio of the planetary gear set220; the R2/S2 value is the tooth ratio of the planetary gear set 230;and the R3/S3 value is the tooth ratio of the planetary gear set 240.Also depicted in FIG. 3b is a chart representing the ratio steps betweenadjacent forward speed ratios and the reverse speed ratio. For example,the first to second ratio interchange has a step of 1.67. It can also bereadily determined from the truth table of FIG. 3b that all of thesingle step forward ratio interchanges are of the single transitionvariety.

A powertrain 310, shown in FIG. 4a, includes the engine and torqueconverter 12, a planetary transmission 314, and the final drivemechanism 16. The planetary transmission 314 includes an input shaft 17continuously connected with the engine and torque converter 12, aplanetary gear arrangement 318, and output shaft 19 continuouslyconnected with the final drive mechanism 16. The planetary geararrangement 318 includes three planetary gear sets 320, 330 and 340.

The planetary gear set 320 includes a sun gear member 322, a ring gearmember 324, and a planet carrier assembly member 326. The planet carrierassembly member 326 includes a plurality of pinion gears 327 rotatablymounted on a carrier member 329 and disposed in meshing relationshipwith both the sun gear member 322 and the ring gear member 324.

The planetary gear set 330 includes a sun gear member 332, a ring gearmember 334, and a planet carrier assembly member 336. The planet carrierassembly member 336 includes a plurality of pinion gears 337 rotatablymounted on a carrier member 339 and disposed in meshing relationshipwith both the sun gear member 332 and the ring gear member 334.

The planetary gear set 340 includes a sun gear member 342, a ring gearmember 344, and a planet carrier assembly member 346. The planet carrierassembly member 346 includes a plurality of pinion gears 347 rotatablymounted on a carrier member 349 and disposed in meshing relationshipwith both the sun gear member 342 and the ring gear member 344.

The planetary gear arrangement 318 also includes six torque-transmittingmechanisms 350, 352, 354, 356, 358 and 359. The torque-transmittingmechanisms 350, 352, 354 and 356 are of the rotating typetorque-transmitting mechanisms, commonly termed clutches. Thetorque-transmitting mechanisms 358 and 359 are stationary typetorque-transmitting mechanisms, commonly termed brakes or reactionclutches.

The input shaft 17 is not continuously connected with any planetary gearmember. The output shaft 19 is continuously connected with the planetcarrier assembly member 346. The ring gear member 324 is continuouslyconnected with the ring gear member 334 through the interconnectingmember 370. The sun gear member 322 is continuously connected with thesun gear member 342 through the interconnecting member 372. The planetcarrier assembly member 336 is continuously connected with the ring gearmember 344 through the interconnecting member 374.

The planet carrier assembly member 326 is selectively connectable withthe input shaft 17 through the clutch 350. The sun gear member 332 isselectively connectable with the input shaft 17 through the clutch 352.The ring gear member 334 is selectively connectable with the sun gearmember 332 through the clutch 354. The ring gear member 334 isselectively connectable with the planet carrier assembly member 346through the clutch 356. The sun gear member 322 is selectivelyconnectable with the transmission housing 360 through the brake 358. Theplanet carrier assembly member 326 is selectively connectable with thetransmission housing member 360 through the brake 359.

The truth tables given in FIGS. 4b, 5 b, 6 b, 7 b, 8 b, 9 b, 10 b, 11 b,12 b, 13 b and 14 b show the engagement sequences for thetorque-transmitting mechanisms to provide at least seven forward speedratios and one reverse speed ratio. As shown and described above for theconfiguration in FIGS. 1a, 2 a and 3 a, those skilled in the art willunderstand from the respective truth tables how the speed ratios areestablished through the planetary gear sets identified in the writtendescription.

The truth table shown in FIG. 4b describes the engagement combinationand the engagement sequence necessary to provide the reverse drive ratioand eight forward speed ratios. A sample of the numerical values for theratios is also provided in the truth table of FIG. 4b. These values aredetermined utilizing the ring gear/sun gear tooth ratios also given inFIG. 4b. The R1/S1 value is the tooth ratio for the planetary gear set320; the R2/S2 value is the tooth ratio for the planetary gear set 330;and the R3/S3 value is the tooth ratio for the planetary gear set 340.Also given in FIG. 4b is a chart describing the step ratios between theadjacent forward speed ratios and the reverse to first forward speedratio. For example, the first to second forward speed ratio step is1.42. It can be readily determined from the truth table of FIG. 4b thateach of the forward single step ratio interchanges is a singletransition shift. The chart also shows that the torque-transmittingmechanisms 352 and 359 can be engaged through the neutral condition tosimplify the forward/reverse interchange.

Those skilled in the art will recognize that the numerical values of thereverse and sixth forward speed ratios are determined utilizing the ringgear/sun gear tooth ratios of the planetary gear sets 320 and 340. Thenumerical values of the first and fifth forward speed ratios aredetermined utilizing the ring gear/sun gear tooth ratios of theplanetary gear sets 320, 330 and 340. The numerical values of the secondand third forward speed ratios are determined utilizing the ringgear/sun gear tooth ratios of the planetary gear sets 330 and 340. Thenumerical value of the fourth forward speed ratio is determinedutilizing the ring gear/sun gear tooth ratio of the planetary gear set340. The numerical value of the seventh forward speed ratio is 1. Thenumerical value of the eighth forward speed ratio is determinedutilizing the ring gear/sun gear tooth ratio of the planetary gear set320.

A powertrain 410, shown in FIG. 5a, includes the engine and torqueconverter 12, a planetary transmission 414 and the final drive mechanism16. The planetary transmission 414 includes a planetary gear arrangement418, input shaft 17 and output shaft 19. The planetary gear arrangement418 includes three simple planetary gear sets 420, 430 and 440. 1161 Theplanetary gear set 420 includes a sun gear member 422, a ring gearmember 424, and a planet carrier assembly 426. The planet carrierassembly 426 includes a plurality of pinion gears 427 rotatably mountedon a carrier member 429 and disposed in meshing relationship with boththe sun gear member 422 and the ring gear member 424.

The planetary gear set 430 includes a sun gear member 432, a ring gearmember 434, and a planet carrier assembly member 436. The planet carrierassembly member 436 includes a plurality of pinion gears 437 rotatablymounted on a carrier member 439 and disposed in meshing relationshipwith both the sun gear member 432 and the ring gear member 434.

The planetary gear set 440 includes a sun gear member 442, a ring gearmember 444, and a planet carrier assembly member 446. The planet carrierassembly member 446 includes a plurality of pinion gears 447 rotatablymounted on a carrier member 449 and disposed in meshing relationshipwith both the sun gear member 442 and the ring gear member 444.

The planetary gear arrangement 418 also includes six torque-transmittingmechanisms 450, 452, 454, 456, 458 and 459. The torque-transmittingmechanisms 450, 452 and 454 are rotating-type torque-transmittingmechanisms, commonly termed clutches. The torque-transmitting mechanisms456, 458 and 459 are stationary-type torque-transmitting mechanisms,commonly termed brakes or reaction clutches.

The input shaft 17 is not continuously connected with any planetary gearmember. The output shaft 19 is continuously connected with the ring gearmember 434. The planet carrier assembly member 426 is continuouslyconnected with the planet carrier assembly member 436 through theinterconnecting member 470. The sun gear member 422 is continuouslyconnected with the sun gear member 442 through the interconnectingmember 472. The sun gear member 432 is continuously connected with theplanet carrier assembly member 446 through the interconnecting member474.

The planet carrier assembly member 426 is selectively connectable withthe input shaft 17 through the clutch 450. The sun gear member 442 isselectively connectable with the input shaft 17 through the clutch 452.The ring gear member 424 is selectively connectable with the sun gearmember 432 through the clutch 454. The planet carrier assembly member436 is selectively connectable with the transmission housing 460 throughbrake 456. The planet carrier assembly member 446 is selectivelyconnectable with the transmission housing 460 through the brake 458. Thering gear member 444 is selectively connectable with the transmissionhousing 460 through the brake 459.

The truth table shown in FIG. 5b describes the engagement combinationand sequence of the torque-transmitting mechanisms 450, 452, 454, 456,458 and 459 that are employed to provide the reverse drive ratio and theseven forward speed ratios. It should be noted that thetorque-transmitting mechanisms 452 and 456 are engaged through theneutral condition to simplify the forward/reverse interchange.

Also given in the truth table of FIG. 5b is a set of numerical valuesthat are attainable with the present invention utilizing the ringgear/sun gear tooth ratios shown. The R1/S1 value is the tooth ratio ofthe planetary gear set 420; the R2/S2 value is the tooth ratio of theplanetary gear set 430; and the R3/S3 value is the tooth ratio of theplanetary gear set 440.

FIG. 5b also provides a chart of the ratio steps between adjacentforward ratios and between the reverse and first forward ratio. Forexample, the ratio step between the first and second forward ratios is1.87. Those skilled in the art will recognize that the numerical valuesof the reverse and sixth forward speed ratios are determined utilizingthe ring gear/sun gear tooth ratios of the planetary gear sets 430 and440. The numerical values of the first and second forward speed ratiosare determined utilizing the ring gear/sun gear tooth ratios of theplanetary gear sets 420 and 430. The numerical values of the third andfifth forward speed ratios are determined utilizing the ring gear/sungear tooth ratios of the planetary gear sets 420, 430 and 440. Thenumerical value of the fourth forward speed ratio is 1. The numericalvalue of the seventh forward speed ratio is determined utilizing thering gear/sun gear tooth ratio of the planetary gear set 430.

A powertrain 510, shown in FIG. 6a, includes an engine and torqueconverter 12, a planetary gear transmission 514 and the final drivemechanism 16. The planetary transmission 514 includes the input shaft17, a planetary gear arrangement 518 and the output shaft 19. Theplanetary gear arrangement 518 includes three planetary gear sets 520,530 and 540.

The planetary gear set 520 includes a sun gear member 522, a ring gearmember 524, and a planet carrier assembly 526. The planet carrierassembly 526 includes a plurality of pinion gears 527 rotatably mountedon a carrier member 529 and disposed in meshing relationship with boththe sun gear member 522 and the ring gear member 524.

The planetary gear set 530 includes a sun gear member 532, a ring gearmember 534, and a planet carrier assembly member 536. The planet carrierassembly member 536 includes a plurality of pinion gears 537 rotatablymounted on a carrier member 539 and disposed in meshing relationshipwith both the sun gear member 532 and the ring gear member 534.

The planetary gear set 540 includes a sun gear member 542, a ring gearmember 544, and a planet carrier assembly member 546. The planet carrierassembly member 546 includes a plurality of pinion gears 547 rotatablymounted on a carrier member 549 and disposed in meshing relationshipwith both the sun gear member 542 and the ring gear member 544.

The planetary gear arrangement 518 also includes six torque-transmittingmechanisms 550, 552, 554, 556, 558 and 559. The torque-transmittingmechanisms 550, 552, 554 and 556 are rotating-type torque-transmittingmechanisms, commonly termed clutches. The torque-transmitting mechanisms558 and 559 are stationary-type torque-transmitting mechanisms, commonlytermed brakes or reaction clutches.

The input shaft 17 is not continuously connected with any planetary gearmember. The output shaft 19 is continuously connected with the planetcarrier assembly member 546. The planet carrier assembly member 526 iscontinuously connected with the planet carrier assembly member 536through the interconnecting member 570. The ring gear member 524 iscontinuously connected with the sun gear member 542 through theinterconnecting member 572. The ring gear member 534 is continuouslyconnected with the planet carrier assembly member 546 through theinterconnecting member 574.

The sun gear member 522 is selectively connectable with the input shaft17 through the clutch 550. The ring gear member 544 is selectivelyconnectable with the input shaft 17 through the clutch 552. The sun gearmember 532 is selectively connectable with the input shaft 17 throughthe clutch 554. The planet carrier assembly member 536 is selectivelyconnectable with the ring gear member 544 through the clutch 556. Thering gear member 524 is selectively connectable with the transmissionhousing 560 through the brake 558. The sun gear member 522 isselectively connectable with the transmission housing 560 through thebrake 559.

The truth table shown in FIG. 6b describes the engagement sequence andcombination of the torque-transmitting mechanisms to provide the reversespeed ratio and eight forward speed ratios. It should be noted that thetorque-transmitting mechanisms 554 and 558 can remain engaged throughthe neutral condition, thereby simplifying the forward/reverseinterchange. It can also be determined from the truth table of FIG. 6bthat all of the single step forward ratio interchanges are of the singletransition variety. The chart of FIG. 6b describes the ratio stepsbetween adjacent forward speed ratios and the ratio step between thereverse and first forward speed ratio.

Those skilled in the art, upon reviewing the truth table and theschematic representation of FIG. 6a, can determine that the numericalvalue of the reverse speed ratio is determined utilizing the ringgear/sun gear tooth ratio of the planetary gear set 530. The numericalvalues of the first and second forward speed ratios are determinedutilizing the ring gear/sun gear tooth ratios of the planetary gear sets520 and 530. The numerical value of the third forward speed ratio isdetermined utilizing the ring gear/sun gear tooth ratios of theplanetary gear sets 530 and 540. The numerical value of the fourthforward speed ratio is determined utilizing the ring gear/sun gear toothratio of the planetary gear set 540. The numerical value of the fifthforward speed ratio is 1. The numerical value of the sixth forward speedratio is determined utilizing the ring gear/sun gear tooth ratios of theplanetary gear sets 520 and 540. The numerical values of the seventh andeighth forward speed ratios are-determined utilizing the ring gear/sungear tooth ratios of the planetary gear sets 520, 530 and 540.

The sample speed ratios given in the truth table are determinedutilizing the tooth ratio values also given in FIG. 6b. The R1/S1 valueis the tooth ratio of the planetary gear set 520; the R2/S2 value is thetooth ratio of the planetary gear set 530; and the R3/S3 value is thetooth ratio of the planetary gear set 540.

A powertrain 610, shown in FIG. 7a, has the engine and torque converter12, a planetary transmission 614 and the final drive mechanism 16. Theplanetary transmission 614 includes the input shaft 17, a planetary geararrangement 618 and the output shaft 19. The planetary gear arrangement618 includes three planetary gear sets 620, 630 and 640.

The planetary gear set 620 includes a sun gear member 622, a ring gearmember 624, and a planet carrier assembly 626. The planet carrierassembly 626 includes a plurality of pinion gears 627 rotatably mountedon a carrier member 629 and disposed in meshing relationship with boththe sun gear member 622 and the ring gear member 624.

The planetary gear set 630 includes a sun gear member 632, a ring gearmember 634, and a planet carrier assembly member 636. The planet carrierassembly member 636 includes a plurality of pinion gears 637 rotatablymounted on a carrier member 639 and disposed in meshing relationshipwith both the sun gear member 632 and the ring gear member 634.

The planetary gear set 640 includes a sun gear member 642, a ring gearmember 644, and a planet carrier assembly member 646. The planet carrierassembly member 646 includes a plurality of pinion gears 647 rotatablymounted on a carrier member 649 and disposed in meshing relationshipwith both the sun gear member 642 and the ring gear member 644.

The planetary gear arrangement 618 also includes six torque-transmittingmechanisms 650, 652, 654, 656, 658 and 659. The torque-transmittingmechanisms 650, 652, 654 and 656 are rotating-type torque-transmittingmechanisms, commonly termed clutches. The torque transmitting mechanisms658 and 659 are stationary-type torque-transmitting mechanisms, commonlytermed brakes or reaction clutches.

The input shaft 17 is not continuously connected with any planetary gearmember. The output shaft 19 is continuously connected with the planetcarrier assembly member 636. The sun gear member 622 is continuouslyconnected with the sun gear member 632 through the interconnectingmember 670. The planet carrier assembly member 626 is continuouslyconnected with the planet carrier assembly member 646 through theinterconnecting member 672. The planet carrier assembly member 636 iscontinuously connected with the ring gear member 644 through theinterconnecting member 674.

The ring gear member 634 is selectively connectable with the input shaft17 through the clutch 650. The sun gear member 642 is selectivelyconnectable with the input shaft 17 through the clutch 652. The ringgear member 634 is selectively connectable with the planet carrierassembly member 646 through the clutch 654. The ring gear member 624 isselectively connectable with the sun gear member 642 through the clutch656. The sun gear member 622 is selectively connectable with thetransmission housing 660 through the brake 658. The ring gear member 624is selectively connectable with the transmission housing 660 through thebrake 659.

The truth table shown in FIG. 7b describes the combination oftorque-transmitting mechanism engagements that will provide the reversedrive ratio and eight forward speed ratios, as well as the sequence ofthese engagements and interchanges. The torque-transmitting mechanisms652 and 659 can be engaged through the neutral condition, therebysimplifying the forward/reverse interchange.

The ratio values given are by way of example and are establishedutilizing the ring gear/sun gear tooth ratios given in FIG. 7b. Forexample, the R1/S1 value is the tooth ratio of the planetary gear set620; the R2/S2 value is the tooth ratio of the planetary gear set 630;and the R3/S3 value is the tooth ratio of the planetary gear set 640.The ratio steps between adjacent forward ratios and the reverse to firstratio are also given in FIG. 7b.

Those skilled in the art will, upon reviewing the truth table of FIG.7b, recognize that the numerical value of the reverse speed ratio isdetermined utilizing the ring gear/sun gear tooth ratio of the planetarygear set 640. The numerical value of the first forward speed ratio isdetermined utilizing the ring gear/sun gear tooth ratios of theplanetary gear sets 620 and 640. The numerical value of the secondforward speed ratio is determined utilizing the ring gear/sun gear toothratios of the planetary gear sets 630 and 640. The numerical value ofthe third forward speed ratio is determined utilizing the ring gear/sungear tooth ratio of the planetary gear set 630. The numerical values ofthe fourth, fifth, seventh and eighth forward speed ratios aredetermined utilizing the ring gear/sun gear tooth ratios of theplanetary gear sets 620, 630 and 640. The numerical value of the sixthforward speed ratio is determined utilizing the ring gear/sun gear toothratios of the planetary gear sets 620 and 630.

A powertrain 710, shown in FIG. 8a, has the conventional engine andtorque converter 12, a planetary transmission 714, and the conventionalfinal drive mechanism 16. The engine and torque converter 12 aredrivingly connected with the planetary transmission 714 through theinput shaft 17. The planetary transmission 714 is drivingly connectedwith the final drive mechanism 16 through the output shaft 19. Theplanetary transmission 714 includes a planetary gear arrangement 718that has a first planetary gear set 720, a second planetary gear set730, and a third planetary gear set 740.

The planetary gear set 720 includes a sun gear member 722, a ring gearmember 724, and a planet carrier assembly 726. The planet carrierassembly 726 includes a plurality of pinion gears 727 and 728 rotatablymounted on a carrier member 729 and disposed in meshing relationshipwith both the sun gear member 722 and the ring gear member 724.

The planetary gear set 730 includes a sun gear member 732, a ring gearmember 734, and a planet carrier assembly member 736. The planet carrierassembly member 736 includes a plurality of pinion gears 737 rotatablymounted on a carrier member 739 and disposed in meshing relationshipwith both the sun gear member 732 and the ring gear member 734.

The planetary gear set 740 includes a sun gear member 742, a ring gearmember 744, and a planet carrier assembly member 746. The planet carrierassembly member 746 includes a plurality of pinion gears 747 rotatablymounted on a carrier member 749 and disposed in meshing relationshipwith both the sun gear member 742 and the ring gear member 744.

The planetary gear arrangement 718 also includes six torque-transmittingmechanisms 750, 752, 754, 756, 758 and 759. The torque-transmittingmechanisms 750, 752, 754 and 756 are rotating-type torque-transmittingmechanisms, commonly termed clutches. The torque-transmitting mechanisms758 and 759 are stationary-type torque transmitting mechanisms, commonlytermed brakes or reaction clutches.

The input shaft 17 is not continuously connected with any planetary gearmember. The output shaft 19 is continuously connected with the planetcarrier assembly member 746. The sun gear member 722 is continuouslyconnected with the planet carrier assembly member 736 through theinterconnecting member 770. The ring gear member 724 is continuouslyconnected with the planet carrier assembly member 746 through theinterconnecting member 772. The ring gear member 734 is continuouslyconnected with the ring gear member 744 through the interconnectingmember 774.

The sun gear member 722 is selectively connectable with the input shaft17 through the clutch 750. The planet carrier assembly member 726 isselectively connectable with the input shaft 17 through the clutch 752.The sun gear member 732 is selectively connectable with the input shaft17 through the clutch 754. The sun gear member 732 is selectivelyconnectable with the sun gear member 742 through clutch 756. The planetcarrier assembly member 726 is selectively connectable with thetransmission housing 760 through the brake 758. The sun gear member 742is selectively connectable with the transmission housing 760 through thebrake 759.

The truth table of FIG. 8b defines the torque-transmitting mechanismengagement sequence utilized for each of the forward speed ratios andthe reverse speed ratio. Also given in the truth table is a set ofnumerical values that are attainable with the present inventionutilizing the ring gear/sun gear tooth ratios given in FIG. 8b. TheR1/S1 value is the tooth ratio of the planetary gear set 720; the R2/S2value is the tooth ratio of the planetary gear set 730; and the R3/S3value is the tooth ratio of the planetary gear set 740.

FIG. 8b also provides a chart of the ratio steps between adjacentforward ratios and between the reverse and first forward ratio. Forexample, the ratio step between the first and second forward ratios is1.99. Those skilled in the art will recognize that the numerical valuesof the reverse, first, sixth and seventh forward speed ratios aredetermined utilizing the ring gear/sun gear tooth ratios of theplanetary gear sets 720, 730 and 740. The numerical value of-the-secondforward speed ratio is determined utilizing the ring gear/sun gear toothratio of the planetary gear set 720. The numerical value of the thirdforward speed ratio is determined utilizing the ring gear/sun gear toothratio of the planetary gear set 740. The numerical value of the fourthforward speed ratio is determined utilizing the ring gear/sun gear toothratios of the planetary gear sets 730 and 740. The numerical value ofthe fifth forward speed ratio is 1.

A powertrain 810, shown in FIG. 9a, has the conventional engine andtorque converter 12, a planetary transmission 814, and the final drivemechanism 16. The engine and torque converter 12 are drivingly connectedwith the planetary transmission 814 through the input shaft 17. Theplanetary transmission 814 is drivingly connected with the final drivemechanism 16 through the output shaft 19. The planetary transmission 814includes a planetary gear arrangement 818 that has a first planetarygear set 820, a second planetary gear set 830, and a third planetarygear set 840.

The planetary gear set 820 includes a sun gear member 822, a ring gearmember 824, and a planet carrier assembly 826. The planet carrierassembly 826 includes a plurality of pinion gears 827 rotatably mountedon a carrier member 829 and disposed in meshing relationship with boththe sun gear member 822 and the ring gear member 824.

The planetary gear set 830 includes a sun gear member 832, a ring gearmember 834, and a planet carrier assembly member 836. The planet carrierassembly member 836 includes a plurality of pinion gears 837 rotatablymounted on a carrier member 839 and disposed in meshing relationshipwith both the sun gear member 832 and the ring gear member 834.

The planetary gear set 840 includes a sun gear member 842, a ring gearmember 844, and a planet carrier assembly member 846. The planet carrierassembly member 846 includes a plurality of pinion gears 847 rotatablymounted on a carrier member 849 and disposed in meshing relationshipwith both the sun gear member 842 and the ring gear member 844.

The planetary gear arrangement 818 also includes six torque-transmittingmechanisms 850, 852, 854, 856, 858 and 859. The torque-transmittingmechanisms 850, 852, 854 and 856 are of the rotating-typetorque-transmitting mechanisms, commonly termed clutches. Thetorque-transmitting mechanisms 858 and 859 are stationary-typetorque-transmitting mechanisms, commonly termed brakes or reactionclutches.

The input shaft 17 is not continuously connected with any planetary gearmember. The output shaft 19 is continuously connected with the ring gearmember 824. The planet carrier assembly member 826 is continuouslyconnected with the planet carrier assembly member 836 through theinterconnecting member 870. The sun gear member 822 is continuouslyconnected with the ring gear member 844 through the interconnectingmember 872. The ring gear member 834 is continuously connected with theplanet carrier assembly member 846 through the interconnecting member874.

The planet carrier assembly member 836 is selectively connectable withthe input shaft 17 through the clutch 850. The sun gear member 832 isselectively connectable with the input shaft 17 through the clutch 852.The ring gear member 844 is selectively connectable with the planetcarrier assembly member 846 through the clutch 854. The ring gear member824 is selectively connectable with the planet carrier assembly member846 through the clutch 856. The planet carrier assembly member 836 isselectively connectable with the transmission housing 860 through thebrake 858. The sun gear member 842 is selectively connectable with thetransmission housing 860 through the brake 859.

The truth table shown in FIG. 9b defines the torque transmittingmechanism engagement sequence that provides the reverse ratio and eightforward speed ratios shown in the truth table and available with theplanetary gear arrangement 818. The truth table indicates that thetorque-transmitting mechanisms 852 and 858 can remain engaged throughthe neutral condition, thereby simplifying the forward/reverseinterchange. A sample of numerical values for the individual ratios isalso given in the truth table of FIG. 9b. These numerical values havebeen calculated using the ring gear/sun gear tooth ratios also given byway of example in FIG. 9b. The R1/S1 value is the tooth ratio of theplanetary gear set 820; the R2/S2 value is the tooth ratio of theplanetary gear set 830; and the R3/S3 value is the tooth ratio of theplanetary gear set 840. It can be readily recognized from the truthtable that all of the single step forward interchanges are singletransition ratio interchanges. FIG. 9b also describes the ratio stepsbetween adjacent forward ratios and between the reverse and firstforward ratio. For example, the ratio step between the first and secondforward ratios is 1.5.

Those skilled in the art of planetary transmissions will recognize thatthe numerical value of the reverse speed ratio is determined utilizingthe ring gear/sun gear tooth ratio of the planetary gear set 830. Thenumerical values of the first and third forward speed ratios aredetermined utilizing the ring gear/sun gear tooth ratios of theplanetary gear sets 820 and 830. The numerical values of the second andfourth forward speed ratios are determined utilizing the ring gear/sungear tooth ratios of the planetary gear sets 820, 830 and 840. Thenumerical values of the fifth and sixth forward speed ratios aredetermined utilizing the ring gear/sun gear tooth ratios of theplanetary gear sets 820 and 840. The numerical value of the seventhforward speed ratio is 1. The numerical value of the eighth forwardspeed ratio is determined utilizing the ring gear/sun gear tooth ratioof the planetary gear set 820.

The powertrain 910, shown in FIG. 10a, includes the conventional engineand torque converter 12, a planetary transmission 914, and theconventional final drive mechanism 16. The engine and torque converter12 are drivingly connected with the planetary transmission 914 throughthe input shaft 17. The planetary transmission 914 is drivinglyconnected with the final drive mechanism 16 through the output shaft 19.The planetary transmission 914 includes a planetary gear arrangement 918that has a first planetary gear set 920, a second planetary gear set930, and a third planetary gear set 940.

The planetary gear set 920 includes a sun gear member 922, a ring gearmember 924, and a planet carrier assembly 926. The planet carrierassembly 926 includes a plurality of pinion gears 927 that are rotatablymounted on a carrier member 929 and disposed in meshing relationshipwith the sun gear member 922 and the ring gear member 924, respectively.

The planetary gear set 930 includes a sun gear member 932, a ring gearmember 934, and a planet carrier assembly member 936. The planet carrierassembly member 936 includes a plurality of pinion gears 937 rotatablymounted on a carrier member 939 and disposed in meshing relationshipwith both the sun gear member 932 and the ring gear member 934.

The planetary gear set 940 includes a sun gear member 942, a ring gearmember 944, and a planet carrier assembly member 946. The planet carrierassembly member 946 includes a plurality of pinion gears 947 rotatablymounted on a carrier member 949 and disposed in meshing relationshipwith both the sun gear member 942 and the ring gear member 944.

The planetary gear arrangement 918 also includes six torque-transmittingmechanisms 950, 952, 954, 956, 958 and 959. The torque-transmittingmechanisms 950, 952, 954 and 956 are of the rotating-typetorque-transmitting mechanisms, commonly termed clutches. Thetorque-transmitting mechanisms 958 and 959 are stationary-typetorque-transmitting mechanisms, commonly termed brakes or reactionclutches.

The input shaft 17 is not continuously connected with any planetary gearmember. The output shaft 19 is continuously connected with the planetcarrier assembly member 926. The sun gear member 922 is continuouslyconnected with the sun gear member 932 through the interconnectingmember 970. The ring gear member 924 is continuously connected with theplanet carrier assembly member 946 through the interconnecting member972. The ring gear member 934 is continuously connected with the sungear member 942 through the interconnecting member 974.

The sun gear member 942 is selectively connectable with the input shaft17 through the clutch 950. The ring gear member 944 is selectivelyconnectable with the input shaft 17 through the clutch 952. The ringgear member 924 is selectively connectable with the planet carrierassembly member 936 through the clutch 954. The planet carrier assemblymember 926 is selectively connectable with the planet carrier assemblymember 936 through the clutch 956. The sun gear member 932 isselectively connectable with the transmission housing 960 through thebrake 958. The ring gear member 944 is selectively connectable with thetransmission housing 960 through the brake 959.

The truth table of FIG. 10b describes the torque-transmitting mechanismengagement sequence utilized to provide the reverse speed ratio andeight forward speed ratios. The truth table also provides a set ofexamples for the ratios for each of the reverse and forward speedratios. These numerical values have been determined utilizing the ringgear/sun gear tooth ratios given in FIG. 10b. The R1/S1 value is thetooth ratio of the planetary gear set 920; the R2/S2 value is the toothratio of the planetary gear set 930; and the R3/S3 value is the toothratio of the planetary gear set 940.

Those skilled in the art, upon reviewing the engagement combinations,will recognize that the numerical values of the reverse, first, sixthand eighth forward speed ratios are determined utilizing the ringgear/sun gear tooth ratios of the planetary gear sets 920, 930 and 940.The numerical value of the second forward speed ratio is determinedutilizing the ring gear/sun gear tooth ratios of the planetary gear sets920 and 940. The numerical value of the third forward speed ratio isdetermined utilizing the ring gear/sun gear tooth ratios of theplanetary gear sets 920 and 930. The numerical value of the fourthforward speed ratio is determined utilizing the ring gear/sun gear toothratio of the planetary gear set 930. The numerical value of the fifthforward speed ratio is determined utilizing the ring gear/sun gear toothratio of the planetary gear set 920. The numerical value of the seventhforward speed ratio is 1.

A powertrain 1010, shown in FIG. 11a, includes the conventional engineand torque converter 12, a planetary transmission 1014, and theconventional final drive mechanism 16. The engine and torque converterare drivingly connected with the planetary transmission 1014 through theinput shaft 17. The planetary transmission 1014 is drivingly connectedwith the final drive mechanism 16 through the output shaft 19. Theplanetary transmission 1014 includes a planetary gear arrangement 1018that has a first planetary gear set 1020, a second planetary gear set1030, and a third planetary gear set 1040.

The planetary gear set 1020 includes a sun gear member 1022, a ring gearmember 1024, and a planet carrier assembly 1026. The planet carrierassembly 1026 includes a plurality of pinion gears 1027 rotatablymounted on a carrier member 1029 and disposed in meshing relationshipwith both the sun gear member 1022 and the ring gear member 1024.

The planetary gear set 1030 includes a sun gear member 1032, a ring gearmember 1034, and a planet carrier assembly member 1036. The planetcarrier assembly member 1036 includes a plurality of pinion gears 1037rotatably mounted on a carrier member 1039 and disposed in meshingrelationship with both the sun gear member 1032 and the ring gear member1034.

The planetary gear set 1040 includes a sun gear member 1042, a ring gearmember 1044, and a planet carrier assembly member 1046. The planetcarrier assembly member 1046 includes a plurality of pinion gears 1047rotatably mounted on a carrier member 1049 and disposed in meshingrelationship with both the sun gear member 1042 and the ring gear member1044.

The planetary gear arrangement 1018 also includes sixtorque-transmitting mechanisms 1050, 1052, 1054, 1056, 1058 and 1059.The torque-transmitting mechanisms 1050, 1052, 1054 and 1056 are of therotating-type torque-transmitting mechanisms, commonly termed clutches.The torque-transmitting mechanisms 1058 and 1059 are stationary-typetorque-transmitting mechanisms, commonly termed brakes or reactionclutches.

The input shaft 17 is not continuously connected with any planetary gearmember. The output shaft 19 is continuously connected with the planetcarrier assembly member 1046. The planet carrier assembly member 1026 iscontinuously connected with the ring gear member 1034 through theinterconnecting member 1070. The ring gear member 1024 is continuouslyconnected with the sun gear member 1042 through the interconnectingmember 1072. The sun gear member 1032 is continuously connected with thering gear member 1044 through the interconnecting member 1074.

The sun gear member 1032 is selectively connectable with the input shaft17 through the clutch 1050. The planet carrier assembly member 1026 isselectively connectable with the input shaft 17 through the clutch 1052.The sun gear member 1022 is selectively connectable with the input shaft17 through the clutch 1054. The planet carrier assembly member 1036 isselectively connectable with the planet carrier assembly member 1046through the clutch 1056. The sun gear member 1032 is selectivelyconnectable with the transmission housing 1060 through the brake 1058.The sun gear member 1022 is selectively connectable with thetransmission housing 1060 through the brake 1059.

The truth table shown in FIG. 11b describes the engagement combinationsand the engagement sequence necessary to provide the reverse drive ratioand the seven forward speed ratios. A sample of the numerical values forthe ratios is also provided in the truth table of FIG. 11b. These valuesare determined utilizing the ring gear/sun gear tooth ratios also givenin FIG. 11b. The R1/S1 value is the tooth ratio for the planetary gearset 1020; the R2/S2 value is the tooth ratio for the planetary gear set1030; and the R3/S3 value is the tooth ratio for the planetary gear set1040. Also given in FIG. 11bis a chart describing the step ratiosbetween the adjacent forward speed ratios and the reverse to firstforward speed ratio.

Those skilled in the art will recognize that the numerical values of thereverse, fourth and seventh forward speed ratios are determinedutilizing the ring gear/sun gear tooth ratios of the planetary gear sets1020, 1030 and 1040. The numerical value of the first forward speedratio is determined utilizing the ring gear/sun gear tooth ratio of theplanetary gear set 1040. The numerical values of the second and sixthforward speed ratios are determined utilizing the ring gear/sun geartooth ratios of the planetary gear sets 1020 and 1040. The numericalvalue of the third forward speed ratio is determined utilizing the ringgear/sun gear tooth ratio of the planetary gear set 1030. The numericalvalue of the fifth forward speed ratio is 1.

A powertrain 1110, shown in FIG. 12a, has a conventional engine andtorque converter 12, a planetary transmission 1114, and the conventionalfinal drive mechanism 16. The planetary transmission 1114 includes aplanetary gear arrangement 1118 which is connected with the engine andtorque converter 12 through the input shaft 17 and with the final drivemechanism 16 through the output shaft 19. The planetary gear arrangement1118 includes three planetary gear sets 1120, 1130 and 1140.

The planetary gear set 1120 includes a sun gear member 1122, a ring gearmember 1124, and a planet carrier assembly 1126. The planet carrierassembly 1126 includes a plurality of pinion gears 1127 rotatablymounted on a carrier member 1129 and disposed in meshing relationshipwith both the sun gear member 1122 and the ring gear member 1124.

The planetary gear set 1130 includes a sun gear member 1132, a ring gearmember 1134, and a planet carrier assembly member 1136. The planetcarrier assembly member 1136 includes a plurality of intermeshing piniongears 1137 that are rotatably mounted on a carrier member 1139 anddisposed in meshing relationship with both the sun gear member 1132 andthe ring gear member 1134.

The planetary gear set 1140 includes a sun gear member 1142, a ring gearmember 1144, and a planet carrier assembly member 1146. The planetcarrier assembly member 1146 includes a plurality of pinion gears 1147rotatably mounted on a carrier member 1149 and disposed in meshingrelationship with both the sun gear member 1142 and the ring gear member1144.

The planetary gear arrangement 1118 also includes sixtorque-transmitting mechanisms 1150, 1152, 1154, 1156, 1158 and 1159.The torque-transmitting mechanisms 1150, 1152, 1154 and 1156 are ofrotating-type torque-transmitting mechanisms, commonly termed clutches.The torque-transmitting mechanisms 1158 and 1159 are stationary-typetorque-transmitting mechanisms, commonly termed brakes or reactionclutches.

The input shaft 17 is not continuously connected with any planetary gearmember. The output shaft 19 is continuously connected with the planetcarrier assembly member 1126. The ring gear member 1124 is continuouslyconnected with the planet carrier assembly member 1136 through theinterconnecting member 1170. The planet carrier assembly member 1126 iscontinuously connected with the planet carrier assembly member 1146through the interconnecting member 1172. The ring gear member 1134 iscontinuously connected with the sun gear member 1142 through theinterconnecting member 1174.

The planet carrier assembly member 1136 is selectively connectable withthe input shaft 17 through the clutch 1150. The sun gear member 1132 isselectively connectable with the input shaft 17 through the clutch 1152.The ring gear member 1144 is selectively connectable with the inputshaft 17 through the clutch 1154. The ring gear member 1144 isselectively connectable with the sun gear member 1122 through the clutch1156. The sun gear member 1132 is selectively connectable with thetransmission housing 1160 through the brake 1158. The ring gear member1144 is selectively connectable with the transmission housing 1160through the brake 1159.

The truth table shown in FIG. 12b describes the engagement sequence andengagement combinations utilized with the present family member toprovide a reverse drive ratio and seven forward speed ratios. The truthtable of FIG. 12b also provides a set of example numbers that can beestablished in the planetary gear arrangement 1118 utilizing the ringgear/sun gear tooth ratios. The R1/S1 value is the ring gear/sun geartooth ratio of the planetary gear set 1120; the R2/S2 value is the ringgear/sun gear tooth ratio of the planetary gear set 1130; and the R3/S3value is the ring gear/sun gear tooth ratio of the planetary gear set1140.

The chart of FIG. 12b describes the ratio steps between adjacent forwardspeed ratios for a seven-speed transmission. These step ratios areestablished utilizing the example speed ratios given in the truth table.As also shown in the truth table, the torque-transmitting mechanisms1152 and 1159 can remain engaged through the neutral condition, therebysimplifying the forward/reverse interchange.

Those skilled in the art will recognize that the numerical values of thereverse, fourth and seventh forward speed ratios are determinedutilizing the ring gear/sun gear tooth ratios of the planetary gear sets1120, 1130 and 1140. The numerical value of the first forward speedratio is determined utilizing the ring gear/sun gear tooth ratio of theplanetary gear set 1140. The numerical values of the second and sixthforward speed ratios are determined utilizing the ring gear/sun geartooth ratios of the planetary gear sets 1130 and 1140. The numericalvalue of the third forward speed ratio is determined utilizing the ringgear/sun gear tooth ratio of the planetary gear set 1120. The numericalvalue of the fifth forward speed ratio is 1.

A powertrain 1210, shown in FIG. 13a, includes the conventional engineand torque converter 12, a planetary transmission 1214, and theconventional final drive mechanism 16. The engine and torque converterare drivingly connected with the planetary transmission 1214 through theinput shaft 17. The planetary transmission 1214 is drivingly connectedwith the final drive mechanism 16 through the output shaft 19. Theplanetary transmission 1214 includes a planetary gear arrangement 1218that has a first planetary gear set 1220, a second planetary gear set1230, and a third planetary gear set 1240.

The planetary gear set 1220 includes a sun gear member 1222, a ring gearmember 1224, and a planet carrier assembly 1226. The planet carrierassembly 1226 includes a plurality of pinion gears 1227 rotatablymounted on a carrier member 1229 and disposed in meshing relationshipwith both the sun gear member 1222 and the ring gear member 1224.

The planetary gear set 1230 includes a sun gear member 1232, a ring gearmember 1234, and a planet carrier assembly member 1236. The planetcarrier assembly member 1236 includes a plurality of pinion gears 1237rotatably mounted on a carrier member 1239 and disposed in meshingrelationship with both the sun gear member 1232 and the ring gear member1234.

The planetary gear set 1240 includes a sun gear member 1242, a ring gearmember 1244, and a planet carrier assembly member 1246. The planetcarrier assembly member 1246 includes a plurality of pinion gears 1247rotatably mounted on a carrier member 1249 and disposed in meshingrelationship with both the sun gear member 1242 and the ring gear member1244.

The planetary gear arrangement 1218 also includes six torquetransmitting mechanisms 1250, 1252, 1254, 1256, 1258 and 1259. Thetorque-transmitting mechanisms 1250, 1252, 1254 and 1256 arerotating-type torque-transmitting mechanisms, commonly termed clutches.The torque-transmitting mechanisms 1258 and 1259 are stationary-typetorque-transmitting mechanisms, commonly termed brakes or reactionclutches.

The input shaft 17 is not continuously connected with any planetary gearmember. The output shaft 19 is continuously connected with the ring gearmember 1224. The sun gear member 1222 is continuously connected with thesun gear member 1232 through the interconnecting member 1270. The ringgear member 1224 is continuously connected with the ring gear member1244 through the interconnecting member 1272. The planet carrierassembly member 1236 is continuously connected with the planet carrierassembly member 1246 through the interconnecting member 1274.

The planet carrier assembly member 1226 is selectively connectable withthe input shaft 17 through the clutch 1250. The ring gear member 1234 isselectively connectable with the input shaft 17 through the clutch 1252.The sun gear member 1242 is selectively connectable with the input shaft17 through the clutch 1254. The planet carrier assembly member 1226 isselectively connectable with the planet carrier assembly member 1236through the clutch 1256. The planet carrier assembly member 1226 isselectively connectable with the transmission housing 1260 through thebrake 1258. The sun gear member 1242 is selectively connectable with thetransmission housing 1260 through the brake 1259.

The truth table shown in FIG. 13b describes the engagement combinationsand the engagement sequence necessary to provide the reverse drive ratioand seven forward speed ratios. A sample of the numerical values for theratios is also provided in the truth table of FIG. 13b. These values aredetermined utilizing the ring gear/sun gear tooth ratios also given inFIG. 13b. The R1/S1 value is the tooth ratio for the planetary gear set1220; the R2/S2 value is the tooth ratio for the planetary gear set1230; and the R3/S3 value is the tooth ratio for the planetary gear set1240. Also given in FIG. 13b is a chart describing the step ratiosbetween the adjacent forward speed ratios and the reverse to firstforward speed ratio.

Those skilled in the art will recognize that the numerical values of thereverse and seventh forward speed ratios are determined utilizing thering gear/sun gear tooth ratio of the planetary gear set 1240. Thenumerical values of the first, second, fourth and sixth forward speedratios are determined utilizing the ring gear/sun gear tooth ratios ofthe planetary gear sets 1220, 1230 and 1240. The numerical value of thethird forward speed ratio is determined utilizing the ring gear/sun geartooth ratios of the planetary gear sets 1220 and 1230. The numericalvalue of the fifth forward speed ratio is 1.

A powertrain 1310, shown in FIG. 14a, includes the conventional engineand torque converter 12, a planetary transmission 1314, and theconventional final drive mechanism 16. The engine and torque converterare drivingly connected with the planetary transmission 1314 through theinput shaft 17. The planetary transmission 1314 is drivingly connectedwith the final drive mechanism 16 through the output shaft 19. Theplanetary transmission 1314 includes a planetary gear arrangement 1318that has a first planetary gear set 1320, a second planetary gear set1330, and a third planetary gear set 1340.

The planetary gear set 1320 includes a sun gear member 1322, a ring gearmember 1324, and a planet carrier assembly 1326. The planet carrierassembly 1326 includes a plurality of pinion gears 1327 rotatablymounted on a carrier member 1329 and disposed in meshing relationshipwith both the sun gear member 1322 and the ring gear member 1324.

The planetary gear set 1330 includes a sun gear member 1332, a ring gearmember 1334, and a planet carrier assembly member 1336. The planetcarrier assembly member 1336 includes a plurality of pinion gears 1337rotatably mounted on a carrier member 1339 and disposed in meshingrelationship with both the sun gear member 1332 and the ring gear member1334.

The planetary gear set 1340 includes a sun gear member 1342, a ring gearmember 1344, and a planet carrier assembly member 1346. The planetcarrier assembly member 1346 includes a plurality of pinion gears 1347rotatably mounted on a carrier member 1349 and disposed in meshingrelationship with both the sun gear member 1342 and the ring gear member1344.

The planetary gear arrangement 1318 also includes six torquetransmitting mechanisms 1350, 1352, 1354, 1356, 1358 and 1359. Thetorque-transmitting mechanisms 1350, 1352, 1354 and 1356 are of therotating-type torque-transmitting mechanisms, commonly termed clutches.The torque-transmitting mechanisms 1358 and 1359 are stationary-typetorque transmitting mechanisms, commonly termed brakes or reactionclutches.

The input shaft 17 is not continuously connected with any planetary gearmember. The output shaft 19 is continuously connected with the planetcarrier assembly member 1336. The ring gear member 1324 is continuouslyconnected with the sun gear member 1332 through the interconnectingmember 1370. The planet carrier assembly member 1326 is continuouslyconnected with the ring gear member 1344 through the interconnectingmember 1372. The ring gear member 1334 is continuously connected withthe planet carrier assembly member 1346 through the interconnectingmember 1374.

The sun gear member 1322 is selectively connectable with the input shaft17 through the clutch 1350. The planet carrier assembly member 1346 isselectively connectable with the input shaft 17 through the clutch 1352.The planet carrier assembly member 1336 is selectively connectable withthe ring gear member 1344 through the clutch 1354. The ring gear member1344 is selectively connectable with the planet carrier assembly member1346 through the clutch 1356. The ring gear member 1324 isselectively-connectable with the transmission housing 1360 through thebrake 1358. The sun gear member 1342 is selectively connectable with thetransmission housing 1360 through the brake 1359.

The truth table shown in FIG. 14b describes the engagement combinationsand the engagement sequence necessary to provide the reverse drive ratioand the seven forward speed ratios. A sample of the numerical values forthe ratios is also provided in the truth table of FIG. 14b. These valuesare determined utilizing the ring gear/sun gear tooth ratios also givenin FIG. 14b. The R1/S1 value is the tooth ratio for the planetary gearset 1320; the R2/S2 value is the tooth ratio for the planetary gear set1330; and the R3/S3 value is the tooth ratio for the planetary gear set1340. Also given in FIG. 14b is a chart describing the step ratiosbetween the adjacent forward speed ratios and the reverse to firstforward speed ratio.

Those skilled in the art will recognize that the numerical values of thereverse and second forward speed ratios are determined utilizing thering gear/sun gear tooth ratios of the planetary gear sets 1320 and1330. The numerical values of the first and sixth forward speed ratiosare determined utilizing the ring gear/sun gear tooth ratios of theplanetary gear sets 1320, 1330 and 1340. The numerical value of thethird forward speed ratio is determined utilizing the ring gear/sun geartooth ratio of the planetary gear set 1320. The numerical value of thefourth forward speed ratio is determined utilizing the ring gear/sungear tooth ratio of the planetary gear set 1330. The numerical value ofthe fifth forward speed ratio is 1. The numerical value of the seventhforward speed ratio is determined utilizing the ring gear/sun gear toothratio of the planetary gear set 1340.

While the best modes for carrying out the invention have been describedin detail, those familiar with the art to which this invention relateswill recognize various alternative designs and embodiments forpracticing the invention within the scope of the appended claims.

What is claimed is:
 1. A family of transmissions wherein each familymember comprises: an input shaft; an output shaft; first, second andthird planetary gear sets each having first, second and third members;said output shaft being continuously interconnected with a member ofsaid planetary gear sets; a first interconnecting member continuouslyinterconnecting said first member of said first planetary gear set withsaid first member of said second planetary gear set; a secondinterconnecting member continuously interconnecting said second memberof said first planetary gear set with said first member of said thirdplanetary gear set; a third interconnecting member continuouslyinterconnecting said second member of said second planetary gear setwith said second member of said third planetary gear set; a firsttorque-transmitting mechanism selectively interconnecting said inputshaft with a member of said first, second or third planetary gear set; asecond torque-transmitting mechanism selectively interconnecting saidinput shaft with a member of said first, second or third planetary gearset or said first, second or third interconnecting member; a thirdtorque-transmitting mechanism selectively interconnecting a member ofsaid first, second or third planetary gear set with said input shaft, oranother member of said first, second or third planetary gear set; afourth torque-transmitting mechanism selectively interconnecting amember of said first, second or third planetary gear set or said first,second or third interconnecting member with a stationary member; a fifthtorque-transmitting mechanism selectively interconnecting a member ofsaid first, second or third planetary gear set with said stationarymember; a sixth torque-transmitting mechanism selectivelyinterconnecting a member of said first, second or third planetary gearset with another member of said first, second or third planetary gearset, or with said-stationary member; and said torque-transmittingmechanisms being engaged in combinations of three to establish at leastseven forward speed ratios and a reverse speed ratio between said inputshaft and said output shaft.
 2. The family of transmissions defined inclaim 1, wherein said first, second, third and sixth torque-transmittingmechanisms comprise clutches, and said fourth and fifthtorque-transmitting mechanism comprise brakes.
 3. The family oftransmissions defined in claim 1, wherein said first, second and thirdtorque-transmitting mechanisms comprise clutches, and said fourth, fifthand sixth torque-transmitting mechanisms comprise brakes.
 4. The familyof transmissions defined in claim 1, wherein planet carrier assemblymembers of each of said planetary gear sets are of the single-piniontype.
 5. The family of transmissions defined in claim 1, wherein atleast one planet carrier assembly member of said planetary gear sets isof the double-pinion type.
 6. A family of transmissions having aplurality of family members wherein each family member comprises: aninput shaft; an output shaft; a planetary gear arrangement having first,second and third planetary gear sets, each planetary gear set havingfirst, second and third members; said output shaft being continuouslyinterconnected with a member of said planetary gear sets; a firstinterconnecting member continuously interconnecting said first member ofsaid first planetary gear set with said first member of said secondplanetary gear set; a second interconnecting member continuouslyinterconnecting said second member of said first planetary gear set withsaid first member of said third planetary gear set; a thirdinterconnecting member continuously interconnecting said second memberof said second planetary gear set with said second member of said thirdplanetary gear set; and six torque-transmitting mechanisms forselectively interconnecting said members of said first, second or thirdplanetary gear sets with said input shaft, said output shaft, astationary member or with other members of said planetary gear sets,said six torque-transmitting mechanisms being engaged in combinations ofthree to establish at least seven forward speed ratios and one reversespeed ratio between said input shaft and said output shaft.
 7. Thefamily of transmissions defined in claim 6, wherein a first of said sixtorque-transmitting mechanisms is operable for selectively connectingsaid input shaft with a member of said first, second or third planetarygear set.
 8. The family of transmissions defined in claim 6, wherein asecond of said six torque-transmitting mechanisms is operable forselectively interconnecting said input shaft with a member of saidfirst, second or third planetary gear set, or with said first, second orthird interconnecting member.
 9. The family of transmissions defined inclaim 6, wherein a third of said six torque-transmitting mechanisms isoperable for selectively interconnecting a member of said first, secondor third planetary gear set with said input shaft or with another memberof said first, second or third planetary gear set.
 10. The family oftransmissions defined in claim 6, wherein a fourth of said sixtorque-transmitting mechanisms is selectively operable orinterconnecting a member of said first, second or third planetary gearset or said first, second or third interconnecting member with saidstationary member.
 11. The family of transmission defined in claim 6,wherein a fifth of said six torque-transmitting mechanisms isselectively operable for interconnecting a member of said first, secondor third planetary gear set with said stationary member.
 12. The familyof transmissions defined in claim 6, wherein a sixth of said sixtorque-transmitting mechanisms selectively interconnects a member ofsaid first, second or third planetary gear set with another member ofsaid first, second or third planetary gear set, or with said stationarymember.
 13. The family of transmissions in claim 6, wherein planetcarrier assembly members of each of said planetary gear sets are of thesingle-pinion type.
 14. The family of transmissions in claim 6, whereinat least one planet carrier assembly member of said planetary gear setsis of the double-pinion type.